Location systems in cellular communication networks

• US 20030096624A1
• Filed: 11/15/2002
• Published: 05/22/2003
• Est. Priority Date: 11/16/2001
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Ormson, Richard
• Granted Patent: US 7,224,982 B2
• Time in Patent Office: Days
• US Class Current: 455/456.1
• CPC Class Codes: G01S 1/026 of associated receivers
• CPC Class Codes: G01S 1/045 Receivers
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A location system in a cellular communication network has a first set of base stations 20 which transmits and receives signals in a first communication format. The second set of base stations transmits and receives signals in a second communication format. All the base stations transmit known signals at predetermined times for use in deriving location data. A transmitting and receiving unit 26 of the known location determines the times of arrivals of these signals from each base station in each set of base stations. Similarly, a mobile unit 24 at an unknown location determines the times of arrival of the signals from each base station. By comparing timing differences between signals received at the unknown location and signals received at the known location, it is possible to determine the unknown location therefrom. This can then be transmitted back to either of the sets of base stations.

In a situation where two communication networks are used, the mobile units will be dual mode transmitting and receiving units.

Claims

1. A location system for use in a cellular communication network having a first set of base stations transmitting and receiving signals in a first communication format, a second set of base stations transmitting and receiving signals in a second communication format, wherein all base stations transmit known signals at predetermined times for use in deriving location data, a transmitting and receiving unit at a known location, a transmitting and receiving unit at a location to be determined, means for determining the times of arrival of the known signals from each base station in each set of base stations at the fixed location unit, means for determining the times of arrival of signals from each base station from each set of base stations at the unit at the unknown location, means for comparing timing differences between signals received at the unknown location and signals received at the known location and means for determining the unknown location therefrom.

2. A system as claimed in claim 1, including means for determining timebase differences between the signals transmitted by the two sets of base stations.

3. A system as claimed in claim 1 or 2 in which one of the sets of base stations transmits using a GSM transmission network and the second set of base stations transmits using a UMTS transmission network.

4. A system according to any one of the preceding claims in which the means for determining the unknown location is provided within one of the networks to which one of the sets of base stations is connected.

5. A system as claimed in any one of the preceding claims in which the means for determining the unknown location is provided in the unit at the unknown location.

6. A location system for a cellular communication network substantially as herein described with reference to the accompanying drawings.

7. A dual mode transmitting and receiving unit for use with two cellular communication networks, each comprising a plurality of base stations for transmitting and receiving signals from units, the unit comprising means for deriving location data from both cellular communication networks.

8. A dual mode transmitting and receiving unit for use with two cellular communications network, each comprising a plurality of base stations for transmitting and receiving signals from units, the unit comprising means to derive location data from one cellular communication network and means to report this data over a second cellular communication network.

9. A dual mode transmitting and receiving unit substantially as herein described.